Cranial Nerve Involvement in COVID-19 Survivors


COVID-19, caused by the novel coronavirus SARS-CoV-2, emerged in November 2019 in Wuhan Province, China, and rapidly evolved into a global pandemic, affecting millions of people worldwide (1). The

first detection of COVID-19 cases in Iran occurred in March 2020. Coronaviruses, a large family of viruses, have previously been linked to severe respiratory illnesses such as Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV) (2, 3).

The clinical presentation of COVID-19 can vary significantly depending on various factors, including underlying health conditions, age, and immune system status. Individuals with pre-existing medical conditions, such as diabetes, hypertension, and cardiac disease, as well as the elderly, have been found to be more susceptible to severe forms of the disease (4, 5).

Common symptoms of COVID-19 include fever, fatigue, cough, myalgia, and headache (6). However, emerging research has also reported atypical neurological symptoms among patients, such as coordination deficits, cognitive impairment, paresis, sensory abnormalities, muscle weakness, and pain, as well as disturbances related to the sense of smell (hyposmia) and headaches (7–11).

Additionally, some studies have highlighted the prevalence of cranial nerve involvement and peripheral nervous system symptoms in COVID-19 patients. Reports suggest that olfactory and gustatory issues, as well as gastrointestinal symptoms, may also occur in COVID-19 patients (12, 13).

Furthermore, several cases of peripheral nerve involvement have been documented, including Guillain–Barré syndrome, cranial polyneuritis, neuromuscular junction disorders, and other neuro-ophthalmological disorders (14–16). Notably, cranial nerves VII, VI, and III have been identified as the most frequently affected cranial nerves, resulting in hypogeusia/ageusia, facial palsy, or ophthalmoparesis (16).

Here is a table that summarizes the most common cranial nerves and peripheral nerves that may be involved in COVID-19:

Cranial nerveFunctionPeripheral nerveFunction
CN ISmellOlfactory nerveSmell
CN VIIFacial expressionFacial nerveFacial expression, taste, and tear production
CN VIIIHearing and balanceVestibulocochlear nerveHearing and balance
CN VFacial sensation and chewingTrigeminal nerveFacial sensation, chewing, and corneal reflex
CN IXSwallowing and tasteGlossopharyngeal nerveSwallowing and taste
CN XSwallowing and voiceVagus nerveSwallowing, voice, and heart rate
CN XIShoulder and neck movementSpinal accessory nerveShoulder and neck movement
CN XIITongue movementHypoglossal nerveTongue movement
PNSMovement, sensation, and other functionsMultiple nervesMovement, sensation, and other functions

Guillain–Barré syndrome (GBS) is a rare autoimmune disease that affects the peripheral nervous system, which consists of the nerves that connect the brain and spinal cord to the rest of the body. The immune system mistakenly attacks the protective covering of the nerves, called myelin, causing inflammation and damage.

This results in weakness, tingling, numbness, and sometimes paralysis of the muscles, starting from the feet and hands and spreading upwards. The symptoms usually appear within days or weeks after an infection, such as COVID-19, influenza, or Zika virus, but the exact trigger is unknown. GBS can also affect other parts of the body, such as the eyes, face, heart, lungs, bladder, and bowel.

GBS is diagnosed based on the clinical signs and symptoms, as well as some tests that measure the nerve function and the cerebrospinal fluid (CSF), which is the fluid that surrounds the brain and spinal cord. The treatment aims to reduce the inflammation, support the vital functions, and prevent complications.

The main treatments are immunotherapy, which involves removing or blocking the harmful antibodies from the blood, and plasma exchange, which involves replacing the plasma (the liquid part of the blood) with a donor plasma or a substitute. These treatments can shorten the duration and severity of GBS, but they do not cure it.

The recovery from GBS varies from person to person. Some people may recover fully within weeks or months, while others may have long-term or permanent disabilities, such as muscle weakness, pain, fatigue, or difficulty walking. The prognosis depends on several factors, such as the age, health status, type and extent of nerve damage, and speed of diagnosis and treatment. The mortality rate of GBS is about 4-7%, mainly due to respiratory failure or infections.

GBS is a serious and potentially life-threatening condition that requires urgent medical attention and close monitoring. However, with proper care and rehabilitation, most people can overcome GBS and regain their quality of life.

However, most previous studies have primarily focused on evaluating neurological symptoms and complications during the active phase of COVID-19 infection. The long-term effects of the disease on the nervous system, especially after recovery, remain less explored. Given the potential for persistent neurological symptoms in COVID-19 survivors, further investigation into cranial nerve involvement in this patient group is essential.


With a paucity of research on neurological symptoms in COVID-19 survivors, this study aimed to investigate cranial nerve involvement among patients who have recovered from COVID-19 at Yas Hospital in Tehran. Understanding the potential long-term neurological implications of COVID-19 could aid in identifying persistent symptoms and enabling better management of patients’ post-recovery.


This study was conducted at Yas Hospital in Tehran and included patients who had previously tested positive for COVID-19 and subsequently recovered. The medical records of eligible patients were reviewed to identify cases with cranial nerve involvement. Clinical data, including demographics, comorbidities, symptoms, and neurological examination findings, were collected and analyzed. The prevalence of cranial nerve involvement and its association with other neurological symptoms were evaluated.


The study results indicated that cranial nerve involvement was observed in a significant proportion of COVID-19 survivors at Yas Hospital in Tehran. The most commonly affected cranial nerves were identified, and their association with other neurological symptoms was explored. The study also highlighted the persistence of certain neurological symptoms even after the resolution of COVID-19 infection.


The findings of this study contribute to the growing body of evidence suggesting that COVID-19 can have long-term neurological effects on survivors. Cranial nerve involvement, coupled with other neurological manifestations, underscores the importance of comprehensive neurological assessments for COVID-19 patients during and after their recovery. Moreover, this study emphasizes the need for continued research on the neurological sequelae of COVID-19 and the importance of implementing appropriate follow-up care for survivors.


COVID-19 is not only a respiratory disease but also a complex multi-systemic disorder that can affect various organs, including the nervous system. Neurological symptoms, including cranial nerve involvement, can persist even after recovery from COVID-19. This study at Yas Hospital in Tehran sheds light on the long-term neurological implications of COVID-19 and emphasizes the significance of continued research in this field. Understanding the neurological consequences of COVID-19 is crucial for providing comprehensive care to survivors and developing targeted interventions to improve their quality of life.

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